My traditional nan khatai recipe

Ingredients, Butter, 500grams, Sugar, 500grams, Maida,(white flour) 700grams(or more) Salt, 1/4 tsp Baking soda 1tsp Method, Mix soft butter adding sugar little at a time, till white and smooth. Add flour and salt and baking soda mixture gradually to the mixture little at a time till becomes a smooth dough, mix well for 10 to 15 minutes. Shape nan khatai, brush beaten egg yolk on top. Place them on greased tray and put in-preheated oven on 160 degrees leave them for 20 minutes or till base is golden brown, Let cool and place them in a glass jar.